What do you call a 100000 - sided polygon?

Answer 1

Decemyriagon.
A Myriagon, is a 10,000 sided shape. Deca- is a prifix for denoting ten times. So a decemyriagon is a 100,000 sided shape.

Answer 2

Oh, dude, that's easy. A 100,000-sided polygon is called a hecatontakaitrigon. I mean, who wouldn't know that, right? It's like a shape with so many sides, it's practically a circle trying really hard to be a polygon.